TW201249564A - Ferromagnetic granular powder and method for manufacturing same, as well as anisotropic magnet, bonded magnet, and pressed-powder magnet - Google Patents

Abstract

The present invention relates to a ferromagnetic granular powder that displays commercially high purity and superior magnetic characteristics, and to a method for manufacturing the same. Also provided are an anisotropic magnet, a bonded magnet, and a pressed powder magnet that use the ferromagnetic granular powder. An iron oxide or an iron oxyhydroxide having an average major-axis diameter of 40-5000 nm and an aspect ratio (major-axis diameter/minor-axis diameter) of 1-200 is used as a starting material, aggregated granules are dispersed, and an iron compound granular powder passed through a mesh is subsequently subjected to hydrogen reduction at 160-420 DEG C and to a nitriding process at 130 to 170 DEG C, whereby it is possible to obtain a ferromagnetic granular powder in which a Fe16N2 compound phase is in a ratio of 80% or more as demonstrated by a Mossbauer spectrum, the ferromagnetic grains contain FeO in the granular shell, and the thickness of a FeO film is 5 nm or less.

Description

2012. The invention relates to a ferromagnetic particle powder in which a particle core is FeI6N2 and an outer shell is coated with an oxide film made of very thin FeO, and a method for producing the same. An anisotropic magnet, a bonded magnet, and a powdered magnet using the ferromagnetic particle powder are also provided. [Prior Art] Now, the Nd-Fe-B-based magnetic powder and molded body are used as the necessary magnet for the electric energy and torque of the electric-electric hybrid car, the electric vehicle such as an electric car, an air conditioner, or a washing machine. However, the current theoretical criticality of magnets as Nd-Fe-B based magnet materials. In addition, the low cost of raw materials or the low content of isotopic elements, such as the attractive input of rare earth element materials, are mostly biased towards China, which is a big problem of “China risk”. Therefore, an emphasis is placed on Fe-N compounds such as Fe16N2 which do not contain a rare earth element. Among the Fe-N-based compounds, a--Fe16N2 is a quasi-stabilized compound which crystallizes solid solution nitrogen martensite or pure granular iron for a long period of time. The crystal of the a"-Fel6N2 is bet The structure is expected to be a large magnetic substance having a large saturation magnetization. However, there is very little report that the compound of the quasi-stabilized compound is chemically synthesized as an isolated powder.

Up to now, in order to obtain a single phase of a"-Fe16N2, a method such as a vapor deposition method, a MBE method (molecular line oriented epitaxial growth method), an ion implantation method, a sputtering method, an ammonium nitridation method, etc. has been tried. It is not easy to generate relatively stable γ'-F^N 201249564 or ε-Fq~:)N, and at the same time cause eutectic of metal such as martensite (a, .Fe) or pure iron (a_Fe) to isolate Manufacture of a "_Fei6N2 single-compound. Partial a"-Fei6N2 single compound can be obtained as a film, but the film is suitable for magnetic materials and can not be expanded for wider use. For the known technology of oT-Fe^N2, the proposal has [Patent Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open Publication No. Hei. No. Hei. No. Hei. No. Hei. No. 2000-277311. Patent Document 4: JP-A-2008-108943, Patent Document 5: JP-A-2008-103510, JP-A-2007-335592, JP-A-2007-335592, JP-A-2007-258427, JP-A-2007-258427 Document 8: 曰本特开2007-134614号 Patent Document 9: Day Laid-Open Publication No. 2007-36027 Patent Document 10: Japanese Patent Publication No. 2009-249682 [Patent Document] Patent Document 1:. M. Takahashi, H Shoji, H.

Takahashi, H. Nashi, χ Wakiyama, Μ. Doi, and Μ.

Matsui, J. Appl. Phys., ν〇1·76, pp.6642-6647, 1 994. Non-Patent Document 2: Y. Takahashi, Μ. Katou, Η. Shoji, 201249564 and M. Takahashi, J. Magn. Magn. Mater., Vol. 232, p. 18-26, 2001 ° [Summary of the Invention] The techniques described in Patent Documents 1 to 10 and Non-Patent Documents 1 and 2 cannot be said to be sufficient. In other words, in Patent Document 1, it is described that after the iron particles having the surface oxide film are subjected to reduction treatment, nitriding treatment is performed to obtain Fe16N2', but the maximum energy product is not considered to be increased. Moreover, the nitriding reaction takes a long time (for example, 3 to 10 days), and it cannot be said that it can be industrialized. Further, in Patent Document 2, it is described that the iron oxide powder is subjected to reduction treatment to form a metal iron powder, and the obtained metal iron powder is subjected to nitriding treatment to obtain Fe 6 6N2, which is used as a magnetic particle powder for a magnetic recording medium. It cannot be said that it is applicable as a hard magnetic material having a high maximum energy product BHmax. Further, in Patent Documents 3 to 9, although a very large magnetic substance for a magnetic recording material of pure granular iron is described, a single phase of a"-Fe16N2 cannot be obtained, and a more stable Y'-Fe4N is produced as a mixed phase. Or a metal of s-Fe2~3N, martensite (a'-Fe) or pure iron (α-Fe). Further, in Patent Document 1 ,, the addition of an element is not necessary in detail and its necessity, and the magnetic properties of the resultant product cannot be said to be suitable for use as a hard magnetic material having a high maximum energy product. By. In Non-Patent Documents 1 to 2, a film can be successfully produced a"- 201249564

The use of Fe i όΝ2 single-phase ** film is limited and cannot be used for a wider range of applications. Moreover, when it is a general magnetic material, there is a problem in productivity or economy. Accordingly, the present invention provides a Fe^N2 ferromagnetic particle powder coated on a high-purity and extremely thin FeO, a method for producing the ferromagnetic particle powder, an anisotropic magnet using the powder, a bonded magnet, and a powder Magnet for the purpose. This can be solved by the present invention described below. In other words, the present invention relates to a ferromagnetic particle powder characterized in that a ferromagnetic particle powder composed of a ratio of a Fe i 6N 2 compound phase of a Mossbauer spectrum of 80% or more 'the ferromagnetic particle is outside the particle FeO is present in the shell, and the film thickness of FeO is 5 nm or less (Invention 1). The present invention relates to a ferromagnetic particle powder according to the invention 1 having a volume fraction of Fe 表面 on the surface thereof, which is 25% or less in the FeO volume/particle total volume (Invention 2). The present invention relates to the ferromagnetic particle powder according to the invention 1 or 2, wherein the coercive force Hc is 1.5 k0e or more, and the saturation magnetization as of 5 K is 1 50 emu/g or more (Invention 3). Further, the present invention relates to the present invention. The ferromagnetic particle powder according to any one of Inventions 1 to 3, wherein the nitridation ratio determined by the lattice number is 8 to 13 m ο 1 % (Invention 4). Further, the present invention relates to a method for producing a ferromagnetic particle powder according to any one of the present invention, wherein a BET specific surface area is 5 to 40 m 2 /g (Invention 5)» 201249564 Further, the present invention relates to the present invention. The method for producing a ferromagnetic particle powder according to any one of 1 to 5, wherein an iron oxide or an oxyhydrogen having an average major axis diameter of 40 to 5000 nm and an aspect ratio (long axis diameter/minor axis diameter) of 1 to 200 is used. The iron oxide is used as a starting material, and the agglomerated particle dispersion treatment is carried out so that D:50 is 40 μm or less, and D90 is 150 μm or less, and the iron compound particle powder passing through a sieve of 250 μm or less is subjected to hydrogen reduction at 160 to 42 (TC). The present invention relates to an anisotropic magnet formed by the ferromagnetic particle powder according to any one of the inventions 1 to 5 (the present invention). Further, the present invention relates to a bonded magnet comprising the ferromagnetic particle powder according to any one of the present inventions 1 to 5 (Invention 8). Further, the present invention relates to a powder magnetic magnet, which is a system Containing the present invention 1 to 5 The ferromagnetic particle powder of the present invention is suitable as a magnetic material of extremely high purity and stability. Moreover, the production of the ferromagnetic particle powder of the present invention is also suitable as a magnetic material of extremely high purity and stability. In the method, a high-purity and stable Fel6N2 particle powder can be easily obtained, which is suitable as a method for producing a ferromagnetic particle powder. [Best Mode for Carrying Out the Invention] First, a ferromagnetic particle powder according to the present invention will be described. Strong magnetic particle powder is used by Mössbauer -9-201249564

The composition of the Fe16N2 compound phase is 80% or more. When the Mossbauer spectrum is Fe16N2, it is confirmed that the internal magnetic field is a peak of the iron side of 330 k〇e or more, and particularly, a peak appears in the vicinity of 3 95 kOe. In general, when he is a long time, it is not suitable as a ferromagnetic bonded magnet material because of its strong properties as a soft magnet. Moreover, the present invention can exert sufficient characteristics as a ferromagnetic bonded magnet material. The ferromagnetic particle powder-based particle core is Fe16N2, and FeO exists on the outer shell of the particle, and the simple structure of Fe16N2/FeO from the particle core toward the outer shell is formed. Fel6N2 and FeO are locally bonded, and the crystallography is better. The oxide film of the outer casing does not contain Fe304 or Fe203 or α-Fe. When the Fe16N2 particles are of low purity, they also contain such impurities, but only FeO is formed by high purity. The film thickness of FeO is 5 nm or less, preferably 4 nm or less. With the high purity of Fe16N2, the film thickness of the FeO becomes thin. The FeO film thickness is not particularly limited, and the thinner the film, the better the volume fraction of Fei6N2 contained in the particles is. The lower limit 膜 of the film thickness of FeO is about 0.5 nm. The volume fraction of FeO on the surface of the ferromagnetic particle powder of the present invention is preferably 25% or less in the FeO volume/particle total volume. By increasing the purity of Fel6N2, the volume fraction of FeO is reduced. The preferred FeO has a volume fraction of 23% or less, more preferably 3 to 20 °/«. The ferromagnetic particle powder of the present invention has a coercive force H. The saturation magnetization as of 1.5 kOe or more and 5 K is preferably 150 emu/g or more. When the saturation magnetization 値as and the coercive force He do not reach the above range, it cannot be said that the magnetic properties of the hard magnetic material are sufficient. The preferred coercive force He is 1.6 kOe or more, and the saturation magnetization 値 σ s is 1 800 n m u / g or more. -10- 201249564 The ferromagnetic particle powder of the present invention preferably has a nitridation ratio of 8 to 13 mol% as determined by a lattice number. The preferred nitridation ratio of 11"111〇1% obtained by the chemical composition formula of Fe16N2 is 8.5 to 12.5111 〇 1%, more preferably 9.0 to 12 mol%. The BET specific surface area of the ferromagnetic particle powder of the present invention is preferably 5.0 to 40 m 2 /g. When the BET specific surface area is less than 5 m2/g, the nitriding rate becomes low, and as a result, the Fe16N2 formation rate is lowered, and the desired coercive force or saturation magnetization cannot be obtained. When it exceeds 40 m2/g, the desired saturation magnetization 无法 cannot be obtained. A preferred BET specific surface area is 5.5 to 38 m 2 /g, and more preferably 6.0 to 3 5 m 2 /g. Next, a method of producing the ferromagnetic particle powder of the present invention will be described. The ferromagnetic particle powder of the present invention is obtained by using iron oxide or iron oxyhydroxide having an average major axis diameter of 40 to 5000 nm and an aspect ratio (long axis diameter/minor axis diameter) of 1 to 200 as a starting material. The dispersion treatment is such that D50 is 40 μm or less and D90 is 150 μm or less, and the iron compound particle powder passing through a sieve of 25 μm or less is subjected to hydrogen reduction at 160 to 420 ° C, and nitriding treatment is performed at 130 to 17 (TC). The FeO in the outer shell of the particle is produced by oxidizing the iron metal portion from which the nitrogen at the surface of the particle surface is removed after the nitriding treatment. In the present invention, the average major axis diameter is 40 to 5000 nm, and the aspect ratio is used. (Long axis diameter / short axis diameter) is 1 to 200 iron oxide or iron oxyhydroxide as a starting material.

There is no particular limitation on the iron oxide or iron oxyhydroxide of the starting material, for example, magnetite, Y-Fe2〇3 ' a-Fe2〇3 ' a-FeOOH ' β-FeOOH -11 - 201249564 , γ-FeOOH, FeO and so on. Further, even if the starting material is a single phase, it may contain impurities, and may contain iron oxide or iron oxyhydroxide other than the main phase as an impurity. The particle shape of the iron oxide or iron oxyhydroxide starting material is not particularly special. The restriction may be any of a needle shape, a granular shape, a spindle shape, a rectangular shape, a spherical shape, and the like. The aspect ratio (long axis diameter / short axis diameter) of the iron compound particle powder of the present invention is preferably 1.0 to 200. When it exceeds this range, it is difficult to obtain a ferromagnetic particle powder composed of a Fe16N2 compound phase of the Mössbauer spectrum of 80% or more. The preferred aspect ratio is from 1.0 to 190, and more preferably from 1.0 to 180. The BET specific surface area of the iron compound particle powder of the starting material is preferably 20 to 25 m 2 /g. When the BET specific surface area is less than 20 m2/g, the nitriding treatment is not easily performed, and the ferromagnetic particle powder composed of the Fe16N2 compound phase of the Mössbauer spectrum of 80% or more cannot be obtained. When the BET specific surface area exceeds 250 m2/g, excessive nitriding is caused, so that a ferromagnetic particle powder composed of a Fe16N2 compound phase of the Mössbauer spectrum of 80% or more cannot be obtained. Preferably, the BET specific surface area is from 30 to 200 m 2 /g, more preferably from 35 to 180 m 2 /g. The agglomerated particle diameter of the iron oxide or iron oxyhydroxide in the starting material of the present invention is controlled to a D50 of 40 μm. Hereinafter, D90 is preferably 150 μm or less. Since the starting material uses a powder, the aggregated particle diameter is generally large. The method of making the aggregated particle diameter small is not particularly limited, and for example, it can be ball milled in the presence of an alcohol compound, a ketone compound, or an organic solvent such as toluene, hexane, carbon tetrachloride, or -12-201249564 cyclohexane. Planetary ball grinding, wet; crushing' and jet milling. Preferably, D50 is 35 μm or less, D90 is 125 μm or less, and more preferably D50 is 30 μm or less, and D90 is 100 μm or less. The iron compound particle powder of the present invention is preferably passed through a sieve of 250 μm or less before heat treatment. When the mesh size exceeds 205 μm, it is difficult to obtain a ferromagnetic particle powder which exhibits desired magnetic properties. Preferably, it is 236 μηι or less. For the iron oxyhydroxide, when the dehydration treatment is required, the temperature of the dehydration treatment is 80 to 35 (TC is preferred. When the temperature is less than 80 ° C, the dehydration is hardly possible. When it exceeds 35 (TC), In the subsequent reduction treatment, it is difficult to obtain the iron metal particle powder at a low temperature. The dehydration treatment temperature is preferably 85 to 300 〇 C. After the dehydration treatment, pulverization treatment such as jet milling or ball milling can also be performed. For such treatment, helium gas or an inert gas such as argon gas or nitrogen gas may be used. The dehydration treatment is preferably carried out in an air or nitrogen gas atmosphere. The reduction treatment temperature is 160 to 420 ° C. When the reduction treatment temperature is less than 160 ° C The iron compound particle powder cannot be sufficiently reduced to metal iron. When the reduction treatment temperature exceeds 420 ° C, the iron compound particle powder is reduced, but the nitridation rate is lowered due to sintering between the particles. The preferred reduction treatment temperature is 165~ 380 ° C, more preferably 170 to 350 ° C. The reduction method is not particularly limited, and hydrogen gas can be used, or a reduction method using various halide compounds can be used. -13- 201249564 Time of reduction treatment, no Other restrictions are better than 1. When it is more than 24 hours, it is not easy to carry out nitriding treatment due to the reduction temperature. When it is less than 1 hour, most of them cannot be fully used for 1.5 to 15 hours. It is also possible to use jet milling, ball milling, etc. For the treatments such as helium or argon or nitrogen gas, the nitriding treatment is carried out after the reduction treatment. The temperature of the nitriding treatment is 130 to 170 °C. When the nitridation reaches 130 ° C, the nitriding treatment cannot be sufficiently performed.

A ferromagnetic particle powder consisting of a Fe16N2 compound phase j of the Mössbauer spectrum for the purpose of generating γ'-FqN or e-Fe2~3N. The preferred reduction temperature is ruthenium nitride treatment. The time is preferably within 50 hours. The industrial process is shortly completed in order to increase the industrial productivity per hour. The better is less than 36 hours. The nitriding gas environment is NH3 gas environment. For the outside, a hydrocarbon gas such as N2, H2 or CH4 may be used, and superheated steam may be mixed therein. The nitriding treatment may be carried out by nitriding treatment of approximately 100% as long as the above-mentioned appropriate treatment temperature and time are used. The Fe 6 62 compound phase is oxidized without oxygen when it is taken out after nitriding treatment, and there is almost no 2-4 hours of reduction on the particle shell compared with the post-sintering stage. It is better to perform inert treatment such as pulverization treatment. The temperature is not treated, so it can not be made 80% or more 135 ~ 165. By as much as possible, in addition to nh3 and in this sufficient treatment of nearly 100% of the FeO in the air,得-14 - 20124956 4

The Fel6N2 compound phase is almost 100% strong magnetic particle powder, but as described above, it may not be realized from an industrial viewpoint. According to the review by the inventors of the present invention, it is known that the nitriding treatment is carried out at a ratio of 80% or more of the FeI6N2 compound phase, and even if the metal iron having the particle surface is oxidized in the air after the nitriding treatment, the FeO is generated on the particle shell, as long as When the FeO film thickness is 5 nm or less, the magnetic properties of the ferromagnetic particle powder are not adversely affected. Therefore, it is not necessary to carry out a nitriding treatment in which the Fe16N2 compound phase is 100%, and a nitriding treatment in which the FeO film thickness is about 5 nm or less can be performed. For example, the film thickness of FeO can also be adjusted by appropriately selecting the nitriding treatment time. Next, an anisotropic magnet relating to the present invention will be described. The magnetic properties of the anisotropic magnet of the present invention can be adjusted depending on the intended purpose, and the desired magnetic properties (magnetic coercive force, residual magnetic flux density, and maximum energy product) can be adjusted. There is no particular limitation on the method of magnetic alignment. For example, at a temperature higher than the glass transition temperature, a ferromagnetic particle powder and a dispersant composed of a Fe16N2 compound phase of a Mossbauer spectrum of 80% or more are simultaneously kneaded in an EVA (ethylene-vinyl acetate copolymer) resin. When it is formed, an external magnetic field is applied at a temperature exceeding the glass transition temperature to promote magnetic alignment. Further, a resin such as a urethane and an organic solvent are vigorously mixed with the ferromagnetic particle powder by a manual shaker, and the pulverized ink is applied by mixing or R〇ll-to-R〇ll method. The cloth is printed on the resin film and magnetically aligned as soon as possible through a magnetic field. Further, RIP (Resin Isostatic Pressing) was used to carry out magnetic alignment at a higher density and to make the crystal -15-201249564 magnetic anisotropy to the maximum limit. Insulating coating of cerium oxide or aluminum oxide, zirconium oxide, tin oxide, antimony oxide or the like is carried out in advance in the ferromagnetic particle powder. The method of insulating coating is not particularly limited, and it is deposited by controlling the surface potential of the particles in the solution or by vapor deposition by a CVD method or the like. Next, the resin composition for a bonded magnet according to the present invention will be described. The resin composition for a bonded magnet of the present invention is obtained by dispersing the ferromagnetic particle powder of the present invention in an adhesive resin, and contains 85 to 99% by weight. The ferromagnetic particle powder is obtained, and the residual component is an adhesive resin and other additives. Insulating coating of cerium oxide or aluminum oxide, zirconium oxide, tin oxide, cerium oxide or the like may be carried out in advance in the ferromagnetic particle powder. The method of insulating coating is not particularly limited, and it can be deposited by a method of controlling the surface potential of the particles in the solution or by a CVD method or the like. The above-mentioned adhesive resin can be variously selected depending on the molding method, and a thermoplastic resin can be used for injection molding, extrusion molding, and calender molding, and a thermosetting resin can be used for compression molding. The thermoplastic resin is, for example, Nylon (PA), polypropylene (PP), ethylene vinyl acetate (EVA), polysulfide (PPS), liquid crystal resin (LCP), elastic system, rubber Resin of the system, etc. As the thermosetting resin, for example, an epoxy resin or a phenol resin can be used. Further, in the case of producing a resin composition for a bonded magnet, in order to facilitate molding and to sufficiently exhibit magnetic properties, a known plasticizer, a smoothing agent, a coupling agent, or the like may be added in addition to the adhesive resin required. Things. Further, -16-201249564, other types of magnet powder such as pure ferromagnetic powder may be mixed. These additives may be appropriately selected depending on the purpose, and the plasticizer may be used as a commercial product depending on the resin to be used, and the total amount thereof may be about 0. 0 with respect to the adhesive resin to be used. 1 to 5 · 0% by weight. As the smoothing agent, stearic acid and a derivative thereof, an inorganic smoothing agent, an oil system, or the like can be used, and about 0.01 to 1.0% by weight can be used for the entire bonded magnet. The coupling agent can be used depending on the resin and the filling. For the adhesive resin to be used, about 0.01 to 3.0% by weight can be used. » The resin composition for a bonded magnet of the present invention is obtained by mixing and kneading a ferromagnetic particle powder and a binder resin to obtain a bond. A resin composition for magnets. The mixing may be carried out by a mixer such as a hand mixer, a V-shaped mixer or a Nauta mixer, and the kneading may be carried out by a one-axis kneading machine, a two-axis kneading machine, a kneading type kneading machine, an extrusion kneading machine or the like. Next, the magnetic properties of the bonded magnet of the present invention will be described. The magnetic properties, the magnetic properties, the residual magnetic flux density, and the maximum energy product are adjusted depending on the intended use. The bonded magnet of the present invention can be formed by a known molding method such as injection molding, extrusion molding, compression molding or calender molding by using the resin composition for a bonded magnet, and then magnetizing or pulsing the electromagnet by a usual method. Magnetically, forming a bonded magnet. Next, a sintered magnet relating to the present invention will be described. The sintered magnet of the present invention may be subjected to compression molding and heat treatment of the ferromagnetic particle powder at -17 to 201249564. The conditions of the magnetic field or compression molding are not particularly limited and are adjusted in accordance with the requirements of the pressed powder magnet. For example, the magnetic field is 1 to 15 T and the compression molding pressure is 1.5 to 15 ton/cm 2 . The forming machine is not particularly limited, and CIP or RIP can be used. The shape or size of the shaped body is selected according to the use. An insulating coating of cerium oxide or aluminum oxide, cerium oxide, tin oxide, cerium oxide or the like is carried out in advance in the ferromagnetic particle powder. The method of insulating coating is not particularly limited, and a method of adsorbing the surface potential of the particles in the solution or a method of vapor deposition by a CVD method or the like can be used. Stearic acid or a derivative thereof, an inorganic smoothing agent, and an oil can be used. For example, for the entire bonded magnet, about 0.01 to 1% by weight can be used. As the adhesive, polyolefins such as polyethylene and polypropylene, polyvinyl alcohol, polyethylene oxide, PPS, liquid crystal polymer, PEEK, polyimine, polyether oxime, polyacetal, polyether mill can be used. a thermoplastic resin such as polyfluorene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyoxyphenylene, polydecylamine, polydecylamine or the like or a mixture thereof For the entire bonded magnet, about 0.01 to 5.0% by weight can be used. The heat treatment can be appropriately selected from a continuous furnace or an RF high frequency furnace. The heat treatment conditions are not particularly limited. Next, a description will be given of a dust magnet according to the present invention. The powder magnetic magnet of the present invention is obtained by subjecting the obtained ferromagnetic particle powder to compression molding in a magnetic field. The conditions of the magnetic field or compression molding are not particularly limited, and are adjusted in accordance with the requirements of the produced powder magnet. For example, the magnetic field is 1.0 to 15 T and the compression molding pressure is 1.5 to 15 ton/cm 2 . Forming -18- 201249564 There are no special restrictions on the machine. CIP or RIP can be used. The shape or size of the shaped body is selected according to the application. An insulating coating of cerium oxide or aluminum oxide, chromium oxide, tin oxide, cerium oxide or the like is carried out in advance in the ferromagnetic particle powder. The method of insulating coating is not particularly limited, and it is deposited by controlling the surface potential of the particles in the solution or by vapor deposition by a CVD method or the like. As the smoothing agent, stearic acid or a derivative thereof, an inorganic smoothing agent, or an oil-based temple can be used, and the total amount of the bonded magnets can be 3, and about 0.01 to 1% by weight can be used. As the adhesive, polyolefins such as polyethylene and polypropylene, polyvinyl alcohol, polyethylene oxide, PPS, liquid crystal polymer, PEEK, polyimine, polyether oxime, polyacetal, polyether oxime can be used. , thermoplastic, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyoxyphenylene, polydecylamine, polydecylamine, etc., or a mixture thereof For the entire bonded magnet, about 0.01 to 5.0% by weight can be used. The heat treatment can be appropriately selected from a continuous furnace or an RF high frequency furnace. The heat treatment conditions are not particularly limited. [Embodiment] A typical embodiment of the present invention is as follows: [Examples] The specific surface area 値 of iron oxide or iron oxyhydroxide of the starting material or the obtained ferromagnetic particle powder is determined by a nitrogen BET method. . The primary particle size of the starting material of iron oxide or iron oxyhydroxide or the obtained ferromagnetic particles -19-201249564 sub-powder was measured using a transmission electron microscope (Sakamoto Electronics Co., Ltd. JEM-1200EXII). Calculate the particle size of any selected 120 particles and find the average 値. The composition analysis of the iron oxide or iron oxyhydroxide powder of the starting material or the obtained ferromagnetic particle powder sample is such that the heated sample is dissolved in acid' and the plasma luminescence spectroscopic analyzer is used (SEIKO Electronics Industry Co., Ltd., SPS4000) The analysis was carried out to obtain the constituent phase of the starting material and the obtained ferromagnetic particle powder, and the powder X-ray diffraction apparatus (XRD, Rigaku Co., Ltd., RINT-25 00) was used at the same timing to carry out the transmission electron microscope. (Japan Electronics Co., Ltd., JEM-2000EX), Electron Line Diffraction (ED), Electron Energy Loss Spectrometry (EELS), Energy for Electron Beam Spectroscopic Ultra High Decomposition Energy Electron Microscope (HREM, Hitachi Hitech, HF-2000) Dispersive X-ray spectroscopy (EDS), scanning electron microscopy (STEM) analysis and evaluation were determined. By analysis of ED or EELS, STEM, and EDS, it was confirmed that α-Fe, Fe4N, Fe3-XN, or a trace amount of the added metal element X which is not known as an impurity phase by XRD.

The volume fraction of FeO was evaluated as follows. First, regarding the ferromagnetic particle powder, the position of FeO (oxygen) was confirmed by electron energy loss spectroscopy (EELS). Then, in the TEM observation of the ferromagnetic particle powder, it was confirmed that the center portion of the particle was different from the contrast, and the position of FeO was confirmed based on the result of the electron energy loss spectrometry (EELS), and the thickness of FeO was measured. And the volume fraction of FeO is determined from the thickness of FeO and the shape of the particles. -20- 201249564 The lattice constant of the obtained ferromagnetic particle powder was determined using a powder calender diffraction apparatus (XRD, manufactured by Rigaku Co., Ltd., RINT-2500). The grid number is determined by referring to the following literature to determine the amount of nitrogen. (#Certificate) • Takahashi Yoshiko Tohoku University Graduate School of Engineering, Department of Electrical Engineering, 2001, PhD thesis title: "About (C, N) Adding Fe-based alloy film unbalanced α', α" ' KH Jack, P r 〇c . Roy. Soc., A2 0 8, 216 (1951) “The iron-nitrogen system : the preparation and the crystal structures of nitro gen-austenite (γ) and nitrogen-martensite(a,)'' The magnetic properties of the obtained ferromagnetic particle powder are measured using a physical property measurement system (PPMS + VSM, Japan Quantum·Design) at room temperature (3 0 0K) measured in a magnetic field of 0 to 9 T. The temperature dependence of the magnetic susceptibility of 5 K to 300 K was also evaluated. The Mössbauer measurement of the obtained ferromagnetic particle powder was performed in an argon gas atmosphere. In the kit, the ferromagnetic particle powder is more uniformly mixed with the strontium fat, wrapped in an aluminum hole, and carried out in the liquid at a temperature ranging from xenon to room temperature for 3 to 4 days, and then analyzed by data. Obtaining the obtained ferromagnetic particle powder Proportion of Fe16N2. Review the secondary components such as ct-Fe, Fe4N, Fe3_xN, or iron oxide as the impurity phase during analysis. -21 - 201249564 Determination of particle size distribution of starting materials, solvent using pure water, by Malvern The measurement was carried out by Mastersizer 20 00E. Example 1: <Preparation of starting materials> A spindle shape having an average major axis diameter of 2 10 nm, a medial torse axis ratio of 7, and a specific surface area of n8 rn 2 /g was produced using ferrous sulfate, caustic soda or sodium carbonate. The goethite particles were separated by filtration through a Nutsche funnel (Nutsche), and washed with pure water of 150 ml of pure water for 5 g of the sample, and then dried for 1 night at 13 (TC ventilator). <Pulverization treatment of starting raw material> Next, 3 g of the powder sample was dried by heating in 35 ml of a hexane solvent, and the ruthenium nitride beads and the planetary ball mill substituted with nitrogen were pulverized at room temperature for 4 hours, and then the powder was taken out. When the particle size distribution measurement of the powder is carried out, D50 is 1.6 μm and D90 is 4.4 μm. <Reduction treatment and nitriding treatment of starting materials> The same treatment as above is repeated several times, and the same treatment is used. After the starting material to the vibrating screen only 90μπι extracted sample powder of agglomerated particles of 5〇g oxide was added Ming A track system (125mm > < 125mmx depth 30mm), to stand in a heat treatment furnace. After evacuating the furnace, the argon gas is filled, and the vacuum is repeated three times. "• Then, the hydrogen gas is circulated at a flow rate of 5 L/min, and the temperature is raised to 27 7 t at a temperature increase rate of 5 ° C/min. And keep it for 3 hours, go into the -22-201249564 line to restore. Then, the temperature was lowered to 152 ° C ' to stop the supply of hydrogen. Further, the sample taken out in this state had a specific surface area of α-Fe single phase of 19.5 m 2 /g. Subsequently, a mixed gas of ammonium gas and nitrogen gas and hydrogen gas was mixed at a ratio of 9:0.95 : 0.15 in a total amount of .l 〇L/min, and nitriding treatment was performed at 148 ° C for 7 hours. Then, argon gas was passed through, the temperature was lowered to room temperature, and the supply of argon gas was stopped, and air substitution was carried out for 3 hours. <Analysis of the obtained sample. Evaluation> The obtained particle powder was determined by Mossbauer spectroscopy by XRD and ED as Fe16N2, and the Fe16N2 compound phase was 91%. The average major axis diameter was 195 nm, the specific surface area was 19.7 m2/g, the FeO film thickness was 3 nm, and the volume integral ratio of FeO was 24.6%. Moreover, the nitridation rate was 8.9%. When the magnetic properties were measured, 'saturation magnetization at 5 K 値 os = 238 emu/g, coercive force H (; = 2.1 kOe» Example 2: Same as Example 1, using ferrous sulfate, caustic soda, sodium carbonate to make an average length Spindle-like goethite particles having a shaft diameter of 665 nm, a medial aspect ratio of 19, and a specific surface area of 67 m 2 /g. The product was separated by filtration under a Nou funnel, and washed with pure water of 150 ml of pure water. Then, it was dried for 1 night at a ventilator at 1 25 ° C. In addition, when the particle size distribution of the powder was measured by extracting only agglomerated particles of 250 μm or less with a spray mill and a vibrating screen, the D50 was 17.1 μm, D90. The reduction treatment and the nitridation treatment were carried out in the same manner as in Example 1. -23- 201249564 The reduction treatment was carried out at 2 8 8 t for 2 hours, and the sample taken out in this state was taken. The specific surface area of α-Fe single phase is 9.3 m 2 /g. The nitriding treatment is a particle powder obtained by circulating ammonium gas at 10 L/min and nitriding at 152 ° C for 4 hours, by XRD, ED. Fe16N2 compound as determined by Mossbauer spectrometry for Fel6N2 The average major axis diameter is 630 nm, the specific surface area is 9.4 m 2 /g, the FeO film thickness is 2 nm, and the volume fraction of FeO is 8.6%. Moreover, the nitridation rate is 9.4%. When the magnetic properties are measured, 5K is measured. The saturation magnetization 値 as = 226emu / g, coercive force Hc = 1.9kOe. Example 3: 0.96: 2 in terms of Fe element: 2 ferric sulphate and ferrous sulphate were weighed, in a base state higher than caustic sodium The reaction was carried out to prepare cubic magnetite particles having an average major axis diameter of 50 nm, a medial to lateral axis ratio of 1.01, and a specific surface area of 92 m 2 /g. The material was separated by filtration using a Nou funnel, and was purified to a purity of 200 ml with respect to 5 g of the sample. The water was washed, and then dried for 1.5 days in a 6 m air dryer. The material was wet-bead milled in a toluene solvent using a 15 wt% solid content concentration and 500 μm of a tantalum nitride bead. When the particle size distribution of the powder was measured, the D50 was 8.8 μm and the D90 was 15.2 μm. Further, only the aggregated particles of ι 80 μΓη or less were extracted by a vibrating sieve. Further, the reduction treatment and the nitriding treatment were carried out in the same manner as in Example 2. In the state after the restoration process The sample had a specific surface area of a_Fe single phase of 38.0 m 2 /g. -24 - 201249564 The obtained particle powder was determined by Mossbauer spectroscopy by XRD and ED as Fe6N2 ', and the Fe16N2 compound phase was 85%. The average major axis diameter was 42 nm, the specific surface area was 38.2 m 2 /g, the FeO film thickness was 1.5 nm, the FeO volume fraction was 13.8%, and the nitridation ratio was 11.8%. When the magnetic properties were measured, the saturation magnetization 値 as = 198 emu / g ' coercive force Hc = 1.7 kOe. Example 4: A mixed solution of ferric chloride and sodium citrate was added to a mixed solution of caustic soda and sodium carbonate to foam air, and an average major axis diameter of 2 500 nm, a longitudinal axis ratio of 45.5, and a specific surface area of 85.9 were prepared. Needle-shaped fibrite particles of m2/g. This material was separated by filtration through a Buchner funnel, and washed with purified water of 200 ml of pure water with respect to 5 g of the sample. Then, drying was carried out at 120 ° C for 1 night, and further heat treatment was continued at 350 ° C for 1 hour. After the spray mill, the pulverization treatment was carried out by wet bead milling in the same manner as in the third embodiment. When the particle size distribution of the powder was measured, D50 was 5.4 μm and D90 was 13·9 μη. Further, only the aggregated particles of ΐ80 μm or less were extracted by a vibrating sieve. Further, reduction treatment and nitridation treatment were carried out in the same manner as in Example 2. The reduction was carried out in a hydrogen gas stream at 220 ° C for 8 hours, and the nitridation treatment was carried out in an ammonium gas stream at 14 8 ° C for 14 hours. Further, the sample taken out in the state after the reduction treatment was α _ F e single phase 'specific surface area was 1 4.3 m 2 /g. The obtained particle powder ' was determined by Mossbauer spectroscopy by XRD and ED as Fe16N2, and the compound phase of the F e ! 2 compound was 87%. Moreover, the average long axis ΐΐί diameter is 2450 nm, the specific surface area is i4.6 m2/g, and the FeO film thickness is 2.3 nm, -25- 201249564

The volume fraction of FeO was 9.4% and the nitridation rate was 10.5%. When the magnetic properties were measured, the saturation magnetization 値 as = 223 emu/g and the coercive force He = 2.5 kOe. Comparative Example 1: In the same manner as in Example 1, spindle-shaped goethite particles having an average major axis diameter of 18 〇 nm, a medial and lateral axis ratio of 6.4, and a specific surface area of 1,27 m 2 /g were produced using ferrous chloride, caustic soda or sodium carbonate. The material was separated by filtration through a nucleus funnel, and washed with purified water of a relatively pure water of 550 m1 with respect to 5 g of the sample. Then, it was dried overnight at 130 ° C in a ventilator. Then, the powder was pulverized in an alumina mortar for 3 minutes to prepare a powder sample having a D50 of 63 μm and a D90 of 1 24 μm. Next, reduction treatment and nitridation treatment were carried out in the same manner as in Example 1. The reduction treatment was carried out at 30 (TC) for 2.5 hours. Further, the sample taken out in this state was α-Fe single phase and had a specific surface area of 16.2 m 2 /g. The nitriding treatment was carried out by circulating ammonium gas at 10 L/min. The nitriding treatment was carried out for 11 hours at 158 ° C. After the nitriding treatment, the furnace was replaced with nitrogen at room temperature and directly taken out of the furnace. The obtained particle powder was mixed with X16 and ED in the presence of Fe16N2 and Fe4N. , α-Fe, Fe16N2 compound phase is 79% by Mossbauer spectroscopy, and the average major axis diameter is I60nm, specific surface area is 16.5m2/g 'FeO film thickness is 5.5nm, and FeO volume fraction is 53.4. %, and the nitridation rate is 7.3%. When the magnetic properties are measured, the saturation magnetization of 5K is 178as=178emu/g, and the coercive force is He = 1.2kOe.

Claims (1)

201249564 VII. Patent application garden: 1. A ferromagnetic particle powder characterized by a ferromagnetic particle powder composed of a ratio of a Fel6N2 compound phase of Mössbauer spectrum of 80% or more, the ferromagnetic particle in the particle FeO is present in the outer casing, and the film thickness of FeO is 5 nm or less. 2. The ferromagnetic particle powder according to the first aspect of the invention, wherein the volume fraction of FeO of the ferromagnetic particle powder is 25% or less in the FeO volume/particle total volume. 3. The ferromagnetic particle powder according to claim 1 or 2, wherein the coercive force Hc is 1.5 kOe or more, and the saturation magnetization as 5 K is 1 5 Oemu/g or more. 4. For example, the scope of claims 1 to 3 The ferromagnetic particle powder according to any one of the preceding claims, wherein the nitridation ratio determined by the lattice number is 8.0 to 13 mol%. 5. The ferromagnetic particle powder according to any one of claims 1 to 4, wherein the BET specific surface area is 5.0 to 40 m 2 /g. 6. The method for producing a ferromagnetic particle powder according to any one of claims 1 to 5, wherein an average major axis diameter of 40 to 5000 nm and an aspect ratio (long axis diameter/minor axis diameter) of 1 are used. The iron oxide or the iron oxyhydroxide of ～200 is used as a starting material, and the agglomerated particle dispersion treatment is carried out so that the D50 is 40 μm or less and the D90 is 150 μm or less, and the iron compound particle powder passing through the sieve of 250 μm or less is placed at 160 to 420 ° C. Hydrogen reduction was carried out, and nitriding treatment was carried out at 130 to 170 °C. 7. An anisotropic magnet formed by the ferromagnetic particle powder according to any one of claims 1 to 5. -27- 201249564 8. A magnetic magnetic particle comprising the ferromagnetic particle powder according to any one of claims 1 to 5. A powder magnetic powder comprising the ferromagnetic particle powder according to any one of the above claims. -28- 201249564 Four designated representative diagrams: (1) The representative representative of the case is: No (2) The symbol of the representative figure is simple: No 201249564 If there is a chemical formula in the case, please disclose the chemical formula that best shows the characteristics of the invention: no